Chromatography is a set of techniques for separating a mixture into its constituents. Generally, in a liquid chromatography analysis, a pump system takes in and delivers a mixture of liquid solvents (and/or other fluids) to a sample manager, where a sample awaits injection into the solvents. The sample is the material under analysis. Examples of samples include complex mixtures of proteins, protein precursors, protein fragments, reaction products, and other compounds, to list but a few. In an isocratic chromatography application, the composition of the liquid solvents remains unchanged, whereas in a gradient chromatography application, the solvent composition varies over time. The mobile phase, comprised of a sample dissolved in a mixture of solvents (and/or other fluids), moves to a point of use, such as a column, which includes a packing material referred to as the stationary phase.
By passing the mobile phase through the column, the various components in the sample separate from each other at different rates and thus elute from the column at different times. A detector receives the separated components from the column and produces an output from which the identity and quantity of the analytes may be determined. Temperature can influence the results of the analysis, affecting such properties as the separation performance of the column and the viscosity of a mobile phase. Therefore, maintaining an accurate constant column temperature can be important to the accuracy and reproducibility of the results.
Systems used for performing chromatography analysis often include fluidic tubing for providing fluid communication between system components. For example, chromatography systems typically include components, such as pumps, valves, columns, and detectors, that are connected together through fluidic (e.g., metallic or polymeric) tubing. The system components and the fluidic tubing are often connected using threaded fittings or bayonet fittings. Connection and disconnection of these fittings (e.g., during assembly, repair, and/or replacement) can require application of torque, e.g., by hand alone or with the use of tools, to establish a fluid tight connection. This can be time consuming, cumbersome (e.g., in cases in which multiple turns are required), and may lead to leaks and/or failure if the fittings are not threaded together properly and/or if adequate torque is not applied when the connection is made.
In modern chromatography, systems pressures are being increased and internal fluid volumes are being reduced. As a result, the reliability and seal characteristics of conventional fittings are becoming problematic. As the pressure is raised and the system internal fluid volume is reduced the fitting dead volume and sensitivity to the assemblers skill become impediments to chromatographic quality. In this regard, establishing fluid tight connections with such conventional fittings can require the use of skilled labor since it is often the case that a high degree of precision is required to ensure the connection is not only fluid tight, but is also devoid of undesirable dead volume which can lead to lost precision in the measured data.